The Legend of the Crystal Empire

A young filly is discovered in the Frozen North

The unicorn daughter of the royal family changes crystallings for the better, and for this she earns her wings.

Due to the customs observed by the royal family, Nebula must be trained to become the next ruler of the Empire.

Nebula cannot rule alone, so a colt is chosen to receive tutelage and rule alongside her.

Years pass, and the day of the coronation arrives

Celebrations are held and gifts are bestowed upon the new king and queen.

The king and queen retire to their bedchambers, and Nebula is soon asleep, but Coal is drawn to the red gem.

Coal is tempted to touch the gem, and immediately finds himself in a dark, smoke-tinged void.

Coal meets Sombra, who is trapped within this void.

Sombra strikes a deal with Coal; the dragon king will share his power with Coal, and Coal must find a way to release Sombra from imprisonment.

After agreeing to help Sombra, Coal orders a casing and necklace be fashioned for the gem.

Coal works on new armor designs for his soldiers, and sends out convoys to retrieve books.

When Nebula tells her husband they are going to have a baby, Coal's desire for peace grows even more.

Nebula finally confronts Coal over his strange obsessions.

Upon entering Sombra's domain once more, Coal realizes what has been transpiring.

Coal feels a strong pressure in his mind as Sombra gains control over him.

A pegasus filly is born to the king and queen, and a royal crystalling is planned.

The day of the crystalling arrives, but it does not go as planned.

King Sombra uses his magic to kill the previous rulers.

Though Nebula had not been trained in combat magic, she engages Sombra, who is not yet used to his new body.

When King Sombra gains the upper hoof and strikes Nebula down, she destroys the Dragon Amulet with a beam of magic.

Though Nebula managed to destroy the Amulet, this did not reverse the effect it had on Coal, and King Sombra became the new ruler of the Crystal Empire.

In her weakened state, Nebula cannot stop King Sombra from taking her prisoner, and locking her up at the top of the castle with the Crystal Heart.

Assuming the Crystal Ponies will attempt to rescue their queen, King Sombra experiments and strengthens his defenses.

Several servants attempt a revolt, and King Sombra quickly stamps it out.

King Sombra sends his new soldiers on a mission; kill every single unicorn and pegasus in the Empire.

In central Equestria, Celestia and Luna take notice of the absence of skylights and envoys from the Crystal Empire, and send a team of soldiers to pay the Empire a visit.

When the soldiers return, they report the blizzard and walls of shadowflame, and the two sisters suspect trouble.

Celestia and Luna use their magic to get through the shadowflame wall, and enter the Crystal Empire.

When the Crystal Ponies try to have the sisters protect their crystal princess, King Sombra's soldiers find them and capture Cadence.

Celestia and Luna are escorted to the throne room, where they meet King Sombra.

Sensing the vast amounts of magic the sisters possess, King Sombra leads them to Nebula's prison so he can apply magic-nullifying crystals to them.

King Sombra miscalculates, and the sisters are able to overthrow him, turning the tyrannical king into shadows.

Celestia and Luna rescue Cadence and intend to help the Crystal Ponies, but before they can, the Crystal Empire vanishes into thin air.